The post-1948 period saw the African National Congress (ANC) abandoning its traditional reliance on tactics of moderation such as petitions and deputations. In December 1949, with the support of the ANC Youth League, a new leadership came to power in the ANC. Walter Sisulu was elected secretary-general and a number of Youth Leaguers were elected to the national executive, including Oliver Tambo , Sisulu's successor. The period 1950 -1952 began with a commitment to militant African nationalism and mass action and to tactics of boycotts, strikes and civil disobedience. The period culminated in the Defiance Campaign, the largest scale non-violent resistance ever seen in South Africa and the first campaign pursued jointly by all racial groups under the leadership of the ANC and the South African Indian Congress (SAIC).